In chemistry, oxidation and reduction are taken as two mutually exclusive events. For example, if life is oxidation then death is taken as reduction, taking off a flight is oxidation then standing would be reduction and so many other. In brief it is used as redox in chemical science.

There are so many conceptual facts regarding redox such as adding oxygen or oxygenation, removing hydrogen or dehydrogenation, removing electron or dielectronation are fixed for oxidation and their corresponding antonyms would be reduction processes. Simple way of judging whether a monatomic species has under gone oxidation or reduction is to note if the charge number of species has changed. It is possible to assign to an atom in polyatomic species an operative charge number called their oxidation number or state. (O.N. or O.S.). There is no standard symbol for this quantity so we say it is φ . An O.N. is assigned to an element in a compound by assuming that it is present as ion with a characteristic charge for instance oxygen is present as O(–II) and fluorine as F(–I) and some time it may be hypothetical also. For example

For ZnO ≡

For NH 3 ≡ In continuation to our study, species promoting oxidation are named as oxidant and those promoting reduction are termed as reductant. At the same time their equivalent weights is the ratio of their molecular weight and change is O. N. ( Δφ ) involving one molecule/formula unit of the reactant i.e., molecular weight divided by number of electrons lost or gained by one molecule/formula during their respective action.

Based on the above discussion answer the following objective question having one best answer.

(i) Which corresponds to oxidation action